SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '00de405ed60126b967e75362f20f54eadb0457ebcb2c7800158305eb174b10f7' 
  AND token = 'btStTnOf6sIIOl1F50eN+NpDfN2KG50Pn+u3lXzIGjA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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