SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9acea142c81f0083d732d47dfa88b3a2f67e438ae8f540e978726a4ad16fcdb' 
  AND token = 'RPrcqKNdk5tv25JNtUC8XUIaMxgYLxAhUagxUOipjJE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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