SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '04846578a33bf1b507daa364b850f0943c48ec811afc6ab4b60ca5d8d7874f75' 
  AND token = 'jhEGJENEoK/2xGqF9/aLWavGFQfOHsFftfagn6eWLyI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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