SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e481b9c1a562bd3c1e9538ff534a730be859e3e0a695cf983a28cc7403ff8096' 
  AND token = '0qAPQUcAa0hKjNyiUGYV50EJ3ujDIQaNKCepSMiwvoE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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