SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46003cf7366f0386f47ca6f77a85f7cfaa09404d403740dcce1ffe026d7d8b17' 
  AND token = 'oVFNCZPFCBAZDeNfeVDl+DDoLFKirerrMp0xNeq23ds=' 
  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"
    }
  }
}