SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d1c9bbf22d21c9a9dddfd29d17014238b16183f6277db22bd673f646b476224' 
  AND token = 'uSem0UD+SMnnhX9oakfcbDtHR0kCUyP426zhpZf10Gw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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