SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd7c3a605427f48f0278f74d230fbd2d4a12d8004fc2c6b4110e53aa02dab846' 
  AND token = 'XOFRHLjGDBd97VTt3nwzZBGyF1fKJu2tyOG1+oZVhKk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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