SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '822edc6530e3da734cdc107aabe0751df6d3681ecd89f538516bb15ef461643e' 
  AND token = 'efhYrExh/5tizXTfx17mYflRBpyudGq2DAZH8xoGaNs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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