SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa1998d57019b6e1adb38d54834a03e834062d656daba831e08ff5e3dff37229' 
  AND token = 'OBLa8dgv/QNi8EGQDM7mCnFzsbXvXPwU99OkEJ7dZKI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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