SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3c682c702e129519bf78eb2b29717bdcad23004d1942f7047c44af1d907746c' 
  AND token = 'G9RSgAKOHmeID7v9JRrE0g31kvvIi+ZE9RDKBbgsyZs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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