SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67fb6d8edf3c8fc5e5c81944269ebc721ae63368602649d1b237a81308912534' 
  AND token = 'XdfjDWr+zlubvDU6xf6KrE22uj3YrsK2gNW3HA9WMC8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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