SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc29da7ab9afb30fb02d19c46f57187029ccf17fec194ded6375f1df637c0445' 
  AND token = 'xsXzj0lpC1eI9q43996RI6xo/uHNeWMQWfAgtcL344A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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