SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc2b936929d668a503aff628f0c43e23b50c3e3c1f3242a2bd7509059b742d93' 
  AND token = 'apCe4W5N13cYQ17WUJgpX24xwmaKYniTul53/ydVQqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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