SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a90ab825a82b982522e0b63e923853abe7b2a9d48b4b6815d87022d526c9944d' 
  AND token = 'ozn8ZiKZ0mWUy/YDqgAfks7fv1hBGPddS0W4TXQKgVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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