SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4e6624a6b64dc759bb8dc6f187f08e62dfba8768ae49d20df129bea3054331b' 
  AND token = 'MWVKGWK4x71IthTmbUQ55py9jOOarw3EOd74Qqoq3X8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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