SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c9065587dc57d639890ed5f25f546843721f0fea9d4d0d9e6b3e641b50af635' 
  AND token = '+/lYjqirNX3eZUDhswJIZqvFCLg3djlPrDsmVVh0nWY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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