SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e23304b6d6b9d849fca6c91e8112dd87e955e04ae7155087647fd994850a7ff9' 
  AND token = 'RjINQkPFESmF1zgAAeIhxp4kW4P9PmTlC9oOVV9QWS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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