SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0fcf1424ff86598936349ea760bbf5774d454faaf3f876af064c254c530ccc2' 
  AND token = '7+xhl/JEUD33OnE7KsjBLbuZIHX+FGpv8SZZXcoN0nY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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