SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f9bc366972f25a19417062ae5b1e2d782b79cfefc7bbeaaecacd9f44406c70d6' 
  AND token = 'a7tBBYsmD6pggY/8V3+zuUBn6LgoGebUa32tKOL825M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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