SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96ef4278b7278198475b268252fe3944f67e404c18a4bf9952bfb3de98a193cb' 
  AND token = 'DejMO6l3Kv5Imb+J/VcrQ0vUkZmLATVVySzgN3moKNA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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