SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42b133f54967d050b2748c7d66079e4c1877799d79eb981cf7d2b09dd5bde7f5' 
  AND token = 'bKdSsWKuP0MRUrmiMaIAQ6epDnRAUuo3gUuy+4MRReU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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