SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5cfbae0cdbbed4adfedb6496f6f4ca4564b44f22abef32a0f5776109784d616' 
  AND token = 'axMa0fH/8vPXd6th3C4uYOweqB2Cy8WnkBZPAmQCys0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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