SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16668f9115f8987bcde8c3f966eacbf48c51c3e5387766705809e3c358c19268' 
  AND token = 'zDDG8djFTw5sCNz09nY5ZpkY7NOnrfO6g4spuPzlrdY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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