SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd44a1329e059624aec54fcf1b27e0ab13860de80abf588356a651dec394912f1' 
  AND token = 'OLP2gRz5auiTUYpBk8lV4uMzX65/G5irnZQjvtd0+KI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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