SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9d7bf16ac2bb2cf1a41353ce1ed2e2be8574d905a46ded39b94d3e74c59aa71' 
  AND token = 'KUoGKoMg4h/HsYK26Gxu7S+3MoYgwmLPagwYIBrSbsU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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