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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8a86905993fd1f858b41f3ceff7ca033630fb7de8d2a5b610e95dfeeaebdb04' 
  AND token = 'g6zDN0Di+CWQvFlp8I2oeP1WKryGR4adN+bfP+ZN0EI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}