SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '127089451b1f373291e9f91572c3b388751cf15f6da866480fd177edba75f38b' 
  AND token = 'JtOv1uRB7b/YdM9YmLi20JOPzIsTyVVaRDEb0IgLSac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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