SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '790c099d15db934964658184a0742f81f1f2e6336c0f6169b21ea5962c11904d' 
  AND token = '4irhg+8Dt25W71mOXoPm35mT9h0jwzzUaFHuLryFqf4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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