SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e4d84024ef64e539af09148785f02444b16437bf8582b8516e06107e81f0aad' 
  AND token = '2rwBtqo/g4kpzRGovZgFkAmIQ/qPYlHlI3z8L3Ssrqo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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