SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46431f9ee2b6679740b43aa6f991688b3a9d820dea7401decfa0615609721aa2' 
  AND token = 'TAhhj4d06iV7KwOwhwB72qwhM1YY9wNxRkk2Q79RRoI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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