SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e22a640396f867f74a1ec9e48c72c28fcf2599b73fa6b7bd74b13643c1efd375' 
  AND token = 'vpn3vr3t4+hXt1ouDqmJj5IHZdONV1Hp+BNnny7W8Zw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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