SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f560f1bd8582954c3380794450fba7ac4a4400318730ce6e1c1a4bcd1ff3011' 
  AND token = 'aN6HvOP+5e5qUxyGvKFFhYg1ZBujolV1EyZ8Vsj1r8M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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