SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb04376720b51c624abd978ec5d24ffed17755efc6cb5c863e194bbeb1fe2d4c' 
  AND token = 'nQPM1/1fyjj8qInEhO3zrkNcoAsiI8xY5Q7dVhGyej0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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