SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc6e5a7c828c719c42471a09431a077cd85b911fe751c77eae0954913ecc572e' 
  AND token = '6MfzgjHud9MdaewjQfec9fWFmZMLLhJdkLj/0+5fGuw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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