SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb8aa771ee5f92b6282c89afc2b9242b3d538de59502f071f909e8956e48c1ac' 
  AND token = 'SsuOSKAo3ZqSvtQynLXLLAdx8Dl0EJ7s1sP5MjUXQ9I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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