SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d9ee23443503e245bdca67a707329adaffa4d0558db0742f99dc3927cc6cb8e' 
  AND token = '2B7MZEpmZ/XOIql4i+/7SzihF6JmcdjfMh1ESpFdfmo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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