SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4ead6718caacd519a999a5595d5360f6433126f8e19e12a7f94ff6f2b94557f' 
  AND token = 'RrT4hmbhI44Dalkicfiq2/o3eORsl5aACw5Ct8dShWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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