SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bdd0257477abd571297c534e72943e031d0a62b410a9d6822c340835fedca737' 
  AND token = 'oHareEHlzfInnaXSB8f6HJ9CNsIvVwRa69ROwrbWpD4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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