SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d1113e1faa8097ccf4b83eedc7606e37ad8315837d79a58536a5b13f065b735' 
  AND token = 'fKiDM3CjAHxPGLEW/B6Gqh2wVW0jy7COx5RFJuEyocQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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