SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d541bd18b6bf78135e5b931629cc2a23f3c9e023ae165466378bf72b539836f' 
  AND token = 'ANR0kD/Pt/b3xPn+7KjR42tPqdy+2dPMcEiWynKpAp4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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