SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b63cbbc27f54f605eb681be1d3cebd50e68dbd36026549114c7bb95bacd2e33' 
  AND token = '9UTWSKtME3yDmM9LzH2TBuBDwR5u0dMsH5rfWVVXW88=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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