SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c04b6599484158b45935f433675b5189848e514d88205cadcd449db332ef5ffb' 
  AND token = 'hWJaqs0MWrYSzixMuexcTHOIzCTJQcLggV1VJFLymDk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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