SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1796c0b8791654f3862f19c14e34edd9e205d40e2cd627f1a9bcd03069dcda8' 
  AND token = 'qwi0WINQR0KjDbRcBx9lQvaplc5WyMY5CzBJxzlq7Hs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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