SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd481973eee9a5cffd3df0a7db20d56bfe92a19244509d8dfe21e473c5836f83' 
  AND token = '/5OO3RjBJXCF/jNHsiOMFr8OL+dBqVSCYsO+eKS4Gsk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}