SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '744f6979df1707aa1d11883dc0b9c22089cb6f14b4efce24ad41656d8054833c' 
  AND token = '2txUAzb6GDZzjEYa5YAnfSUJEuJrOin5kXeBddHDXm8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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