SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '210f480d92f2be405dd1127884b9cb1ea377f0e15c5b954cad74e88367e86065' 
  AND token = 'FQJAjgMT2+Q9PAKU2zX837FEUyd298Z2KFPeAgHrT4Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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