SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc0d4daf979ea9b76f972a0e9ad8ea8a54ee226c91205ae71e5b35cda62e0ebf' 
  AND token = 'nDyGCOmVPSxvZZOxMnbbPfMXWe0J7FOUjiwYWyE66RE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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