SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10274c77bd16de54080764316021f66054510729631d38ed247879b39980a9dd' 
  AND token = 'G8S5ENK1ZPk87xxXRJy66SbG2wvyFzXhhIJZbqbgCdY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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