SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '554f40b5b5b8dfe86ecefc6c07b02f966484277da0052ae5b13012f5df423604' 
  AND token = 'ZOUQQbdEKHhoiJqBn8FaU2SZvYjwpf+/LLuf9GdAnaQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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