SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43260ed8377961cefdf2b1fddd75d7b823a97cb512c4196b7e38a415481736f7' 
  AND token = 'QVygR5+odSbgGa0wH38lHH9BLW+IuUue3AXEnAJqQjE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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