SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f59c7c26465293c41b68cab08ec266b731600306418291b800202bc855c1edb8' 
  AND token = 'yRLh9AdRlMgnbPxCaAl2CJfKeFZIWYm9ekM8p9rxEuQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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