SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6edf69885cbead6ba01a91a488877b2b0d75b42b69877599ba1b4e78c455616b' 
  AND token = '0nxQfS32rY2wzUAYqw+aBESsHj7+YbkRhzBOrHyET70=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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