SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d7536d7837b18de9be6638274374e8b7d7d405a067b80e3f250586173d2824a' 
  AND token = 'tzqsPwMlmC1SIYRjfinqXzWzm7osGOLiPEeenVde2Yo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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