SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a30371689a7b4857f0b08e24acb386c8082a8103586288311401fea37227129' 
  AND token = '2CqLJI/pQQDFgTBTdfY3UEXcKhEb+FsnP5jD6DsGF30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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