SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ec1eb623c17185c22c0f87704bef4a4b2bf4d8041c4ebe0a2fe7f3c8a052cf5' 
  AND token = 'bLXVIDlY5vPaRDjXzR/Md1NVsDAoEV5g/15ct3R1ovE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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