SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70e1884c0eeabb66e5892bf59625c1db6ad1b4a8ab8796ab23c54b29e438c220' 
  AND token = 'XbVeb/w+3Vf3IHDvDtlDkyf+9ImSBXTjG+BQaALaIMU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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