SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cdc54784c4d73841f84d5483b282958124718053d778e277ee508a762cf0ec39' 
  AND token = 'V69lpvlKWuDO19ArapWr8/BRaacJAooaLV6fWBUiaKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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