SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '070b440795a67e7cd697742e1207e20e707076a5fce6c986bc63fb842a72b40c' 
  AND token = '5StwIyvMhE39ryASrag5EshqwNQqP7QvinmfNqrYtKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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