SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '432d4eeab4bea4eaf13fb9735a61476ea21208db1327f403dcf3e86f650be4a5' 
  AND token = 'gA/YB3ElCyIhuoy+aQocFNC4+nOBqsAEwl9NCCFkuCs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}