SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2702b68bb3ac4bbcc71002bee05d8361acda0bbbdbe902b87dd92cdd5d239f2' 
  AND token = 'XsvLOYwxOAXF54p2v13xRGdNwx0gGsBlY8tYR0/6D2o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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