SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da616abe5ffdd962aeea15d1f08a98e0a3d34c97f903b5309b38c4b67c10a83a' 
  AND token = '2d61vYT4EWcYZR0GLT2kFrm4mezIBYr3QZpxR9uS5G0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00070

JSON explain

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