SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c8e96f6a273c5eb978685a3a7abe7f8aad7ec873a5e05971608257341f76dd2' 
  AND token = 'DjSxz22IAmRVgTsHUNlvuQV24hrKw9QOil2waloAJ+g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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