SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5340e2c605c60137912c7f37b3d97e5b1b6cd4bbcf7dcd952aa52e726ded62b8' 
  AND token = 'SluQ9aryLAQav0RUhVpJbrOQ0NwCz7hmJoyqOMjX6u4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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