SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3ea9d2512cea186021f7a674169d6cc9a3c84177e14a5b0529a8309a00de394' 
  AND token = 'sqV+Zmvcl+FptNjfj8jV7nq3/wMMUvHtJybPpDzCf5o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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