SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c2544ebce3d3549a813f298bc3824ae4df71aa879ae20c8edc99c8ea5f21341' 
  AND token = 'OIbypZgMMjwk4qjWMdbSV2DYqmVVZSjkgg46jOb6KVQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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