SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68ee33374f47cd153fb892ea1c101c4c75410733729fda009d5dec818e44a7b7' 
  AND token = 'ACRUBTx/B0y9J1EIOUHcjwINBrE35J0lTBAXAx/NriM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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