SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4f9df0bbdd77db2a1b2f045572be72ed05cf2972a76528ab24942c6d32cc615' 
  AND token = 'N3waS48rnddHSs0BJ7H7/MaUhSiDFHf4GyeRV5saCvA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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