SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21ec98b1065c175cf072378a7bccd4e11fc524106c1e02e8e43b3104290fb8ea' 
  AND token = 'h/Z+WGrVXlUbYr/AmyWv4GmE6SOwO/p1Qt3J+2BCna4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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