SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68ef995cd26c8c4cbeac40ae96b48b860df73423c2329370fc8a9826d7ab77ba' 
  AND token = 'Cdd95uojkIqdMWvT5bqhiCmzwoe21L12/9ZwiflZGlA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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