SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4504a79ccc7bc17d9d6c5110614b322282171efb7d18067ca8c278348662d40e' 
  AND token = 'i3JbQQI1kMpJWwZMzcStzm16gdtfEpQXerugMBwF2Ts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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